Snows of Kilimanjaro shrinking rapidly, and likely to be lost

Ohio State University Research News: The remaining ice fields atop famed Mount Kilimanjaro in Tanzania could be gone within two decades and perhaps even sooner, based on the latest survey of the ice fields remaining on the mountain . The findings indicate a major cause of this ice loss is very likely to be the rise in global temperatures. Although changes in cloudiness and precipitation may also play a role, they appear less important, particularly in recent decades.

The first calculation of ice volume loss indicates that from 2000 to 2007, the loss by thinning is now roughly equal to that by shrinking. These predictions, published in the journal Proceedings of the National Academy of Sciences, are among the latest dramatic physical evidence of global climate change.

Paleoclimatologist Lonnie Thompson, professor of earth sciences at Ohio State University, and his colleagues amassed a trail of data showing the rapid loss of ice atop Africa’s highest mountain:

• 85 percent of the ice that covered the mountain in 1912 had been lost by 2007, and 26 percent of the ice there in 2000 is now gone;
• A radioactive signal marking the 1951-52 “Ivy” atomic tests that was detected in 2000 1.6 meters (5.25 feet) below the surface of the Kilimanjaro ice is now lost, with an estimated 2.5 meters (8.2 feet) missing from the top of the current ice fields;
• The presence of elongated bubbles trapped in the frozen ice at the top of one of the cores shows that surface ice has melted and refrozen. There is no evidence of sustained melting anywhere in the rest of the core that dates back 11,700 years;
• Even 4,200 years ago, a drought in that part of Africa that lasted about 300 years and left a thick (about 1-inch) dust layer, was not accompanied by any evidence of melting. These observations confirm that the current climate conditions over Mount Kilimanjaro are unique over the last 11 millennia….

One of a growing number of isolated remnants of ice spires that were once full glaciers in the crater of Mount Kilimanjaro in Africa. Photo by Lonnie Thompson, Ohio State University.